Water-Based Products: What Do I Need to Know?
This is the last post in my DIY Cosmetics for Beginners series! I can't believe that it is ending!?!? It feels like I started it yesterday. Anyway, in this post we are going to be talking about water-based cosmetics. Most of this post is going to be a review from previous posts. This was meant to happen, as I wanted to give the beginners the skills and knowledge to follow along with the recipes that I create. I am going to include how do all the math for conversions and scaling up and down. Don't worry all you will need is a piece of paper and a pen or pencil. You may need to erase, as mistake do happen. So, time for review!
Water-based formulations can be some of the easiest formulations. It can be as simple as adding water-soluble ingredient into water and then adding a preservative and you are done. Simple right! On the other hand, it can be as complex as an emulsions. Which we will come in another post. :) So, water-based formulations can range in difficulty, is what I am try to get at, which is really true for anything in life. Because we are working with water we also have to take into consideration somethings. We need a preservative and we need to check and adjust the pH of your final product. This should not be new. If it is, you may want to look back in the series for additional information and the rational. I said earlier in this series (on the post about pH) that I was going to show you to make the stock solution. So this is going to be the post to do it.
How to create pH stock solutions.
To raise the pH:
Create a 50% citric acid solution
To make a 50 gram sample: In separate containers measure out 25 grams of distilled water in a Heat-safe measuring cup and in another container measure out 25 grams of citric acid. After that, add the citric acid into the water in the glass cup. Don’t do it the other way around. This will need to be heated slightly until the citric acid is fully dissolved the citric acid. Once dissolved then, you are done
These solutions do not need a preservative as the pH is too low for any microbes to grow.
To Lower the pH:
Create a 30% sodium hydroxide solution or alternatively, use undiluted TEA
To make a 50 gram sample: In separate containers, measure out 35 grams of distilled water into a heat-safe measuring cup and in a prep cup measure out 15 grams of sodium hydroxide aka Lye. After that, add the Lye into the water the glass cup. Don’t do it the other way around, we do not need an explosion!. This will need to be heated to fully dissolve the lye. Once dissolved then, you are done!
Idea and some information was used from here. :)
Beginners Cosmetic Science workshops - Free trial
Typically, with adjusting pH, it will not need a drastic change. It can be as little as one drop or as much as ten drops. It all depends on how far off the pH strip or the pH meter tells you. Also, pH adjusting is the last step in your formulation. As some ingredients may alter the pH. So, it is best to leave it to the last step.
Strips Vs. a PH Meter
To be honest it really depends on your budget and what the type of formulations you are doing. For beginners, strips are fine. For more advanced formulators a pH meter would be better. Yes, the meter is more accurate but, you can still get away with. Personally I just use a $16 pH meter form amazon. I still have to get some more practice with it to see if I recommend it or not. It is another option to think about. The really nice ones are around $80 on ebay. So, yea.
Now for the math!
The math that we will be doing is very simple! No tangents, vertical asymptotes, or Pythagorean theorem! :)
I am going to go step-by-step.
Here are the fundamental facts:
Formulations start as percent's.
This is so that we can scale up or down formulations.
100% = 100 grams so it is a 1 to 1 conversion.
Our end goal is to have a formulation that adds up to %100 and nothing more and nothing less.
The general rule is for oil-based formulation your liquid oil portion will be the most. For water-based formulations the majority is water. For emulsions the majority is also water.
So let's say we are going to make a toner spray.
Toners are a majority water.
So we are going to start with 100% water. I have simplified gram to g
100%/100g Distilled water
Essentially, everything after this we are going to be subtracting form the 100g. Like I said before water is the majority of the formulation so, we will be subtracting from the 100%. For the first addition I want to half of the water to be rose water. To do this we take half of 100% to get 50%.
100%-50%=50%
So, it would change to:
50%/50g Distilled water
50%/50g Rose water
For the next addition, we will add 5% glycerin. So, I subtract 5 from 50. We are going to be taking it out of the distilled water so that we can keep the 50% to rose water.
50-5=45
Now the percent of water changes to also include the glycerin. So the recipe changes.
45%/45g Distilled water
50%/50g Rose water
5%/5g Glycerin
The next two ingredients I want to add are a preservative used at 0.5% and Green tea extract at 1%. Again we are going to be subtracting from the distilled water.
45-0.5=44.5
44.5-1=43.5
So the recipe changes to:
43.5%/43.5g Distilled water
50%/50g Rose water
5%/5g Glycerin
1%/1g Green tea extract
0.5%/0.5g Preservative (Liquid Germall Plus as an example)
And then you are done with the math! You also have the recipe to make a 100 gram batch.
let's say you only wanted to make a 50 gram batch or even a 25 gram batch to as big as 200 grams. Well that is easy. For a 50 gram batch divide the whole formulation by 2.
that would look like this
50 grams
43.5%/21.75g Distilled water (43.5 [from original formula] /2= 21.75)
50%/25g Rose water (50/2=25)
5%/2.5g Glycerin
1%/0.5g Green tea extract
0.5%/0.25g Preservative
for 25 grams divide the whole formulation by 4 How? 25* n = 100, Divide both side by 25 to cancel the 25 and to get n by itself. once you are done with that you are left with n=4. so, if your formula = 25 grams we will need to divide 100 by 4.
25 grams
43.5%/10.89g Distilled water (43.5 [from original formula] /4= 10.875 round to 10.89)
50%/12.5g Rose water (50/4=
5%/ 1.25g Glycerin
1%/0.25g Green tea extract
0.5%/0.13g Preservative (Liquid Germall Plus as an example)
To scale up it is simple multiplication. to make a double batch just multiply the whole recipe by 2.
200 gram batch
43.5%/87g Distilled water
50%/100g Rose water
5%/10g Glycerin
1%/2g Green tea extract
0.5%/1g Preservative
And you are done! I hope this was extremely helpful for everyone! let me know what you think! Someone in the comments will be randomly be selected for a shout out next post!
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